This invention relates to penumatic tools in general, and more particularly to a novel type of pneumatic fastening tool.
Pneumatic fastening tools per se are not new in the art. Various examples of such tools are shown in U.S. Pat. Nos. 4,040,554; 3,498,577; 3,905,535; 3,776,445; 3,512,454 and 3,708,096 and the references cited therein. These tools typically comprise a housing, a cylinder disposed in the housing, a piston slidably mounted in the cylinder, a hammer connected to the piston, means for causing the piston to reciprocate within the cylinder so as to drive the hammer from a first retracted position to a second extended position, and a nozzle section for receiving a fastener and positioning it for engagement with the hammer in order to permit the hammer to drive the fastener from the nozzle into a workpiece.
It is sometimes desired that the fastening tool be used to attach small metal parts or members such as washers or name tags to the workpiece. Those tools presently known to be in use generally require a tool operator to manually position the small metal member against the workpiece and hold it there by hand or some other means while he fastens it on. This fastening technique is acceptable for certain applications, but it can present problems, particularly when the member being attached is small in size (thereby making it difficult and dangerous to manually hold the member in place during fastening) or when the member being attached is a washer which has a small center hole to be penetrated and therefore requires critical fastening alignment. In addition, manual positioning of the member being attached may be impossible where the workpiece is very hot, such as when trying to attach a name tag to a newly cast steel ingot.